implementato nodeposition con to string e reverse. aggiunto copyright

deque/Deque.java

@@ -8,6 +8,8 @@ import exceptions.EmptyDequeException;
  * Date: 17/03/14
  * Time: 16:21
  */
+//Copyright (c) 2003 Brown University, Providence, RI
+//Additional modifications and methods by xgiovio
 public interface Deque<E> {
 
     int size();